Modified urea resins and coating compositions containing same



arium MODIFIED UREA RESINS AND COATING COM- POSITIONS CONTAINING SAMEHarry M. Culbertson, Wilbraham, and Frank J. Hahn, Springfield, Mass.,assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation ofDelaware No Drawing. Filed Dec. 4, 1957, Ser. No. 700,538-

13 Claims. (Cl. 260-21) This invention relates to modified urea resinswhich are particularly suitable for use in protective coatingcompositions. to etherified co-condensation products of urea, an N-substituted melamine of the group consisting of N,N'-dicyclohexylmelamine, N,N',N tricyclohexylmelamine and mixtures thereofand formaldehyde. The invention further relates to protective coatingcompositions containing such modified urea resins.

Background of the invention Etherified urea-formaldehyde resins andetherified co: condensates of urea, melamine and formaldehyde haveutility in many industrial fields including the protective coating arts.In particular, protective coating compositions containing blends of suchetherified urea-formaldehyde resins and oil-modified alkyd resins havebeen widely used as baking enamels. While such protective coatingcompositions have many desirable characteristics, their gloss andflexibility are somewhat deficient.

Accordingly, it is an object of this invention to provide novelurea-formaldehyde resins having improved properties.

Another object of the invention is to provide novel urea-formaldehyderesins which are particularly suitable for use in protective coatingcompositions.

Yet another object of the invention is to provide novel protectivecoating compositions containing novel ureaformaldehyde resins.

Other objects and advantages of the invention will be apparent from thefollowing detailed descriptions thereof.

Summary of the invention In accordance with this invention there areprovided novel urea-formaldehyde resins which comprise an etherifiedreaction product of at least 2 mols of a monohydric alcohol containingl-6 carbon atoms and a cocondensation product of 1 mol of urea, -0.3 molof melamine, 0.020.5 mol of an N-substituted melamine of the groupconsisting of N,N'-dicyclohexylmelamine, N,N,N"-tricyclohexylmelamineand mixtures thereof and at least 2 mols of formaldehyde. In a furtherembodiment of the invention there are provided protective coatingcompositions which contain a novel urea-formaldehyde resin of the typedescribed above and an oil-modified alkyd resin. The invention furtherrelates to protective coating compositions containing a ternary mixtureof (1) a novel urea-formaldehyde resin of the type described above, (2)an etherified urea-formaldehyde resin, and (3) an oil-modified alkydresin. In still another embodiment of the invention there are providedprotective coating compositions consisting of a ternary mixture of (1)an oil-modified alkyd resin, (2) an etherified urea-formaldehyde resinand (3) an etherified N-substituted melamine-formaldehyde resin in whichthe N-substituted melamine is selected from the group consisting ofN,N'- dicyclohexylmelamine, N,N',N tricyclohexylmelarn'ine and mixturesthereof. In yet another embodiment of the More particularly, theinvention relates invention there are provided protective coatingcomposi-I tions consisting of a quaternary mixture of (1) an oilmodifiedalkyd resin, (2) a novel urea-formaldehyde resin of the type describedabove, (3) an etherified ureaformaldehyde resin and, (4) an etherifiedN-substituted melamine-formaldehyde resin in which the N-substitutedmelamine is selected from the group consisting of N,Ndicyclohexylmelamine, N,N',N tricyclohexylrnelamine and mixturesthereof.

Experimental The following examples are set forth to illustrate moreclearly the principle and practice of the invention to those skilled inthe art. Unless otherwise stated, where quantities are mentioned theyare parts by weight.

EXAMPLE I Reactants consisting of 63 parts (1.05 'mol) of urea, 39 parts(0.15 mol) of N,N',N"-tricyclohexylmelamine, 86 parts (2.62 mols) ofparaform, 250 parts (3.4 mols) of n-butanol, 28 parts of water and 1part of t'riethanolamine are charged to a reaction vessel equipped withastirrer and a condenser that is fitted with a decanting esterificationhead. The alkaline solution (pH=8.5) is refluxed for 1.0 hour with allof the condensate being returned to the reaction flask.

After adjusting the pH of the system to 6.2 with oxalic acid, thereaction mixture is again heated to reflux. During this phase of thereaction, the decanting head'is set to continuously remove the waterphase which separates in the distillation head and to return the butanolphase to the reaction flask. A total of 45 parts of waterph'ase, isremoved overza- 5-hour period. The balance ofjthe water remaining in thereaction mixture is removed by refluxing the reaction mixture with theesterification head being set for total takeoff. The distillation iscontinued until the boiling point of the distillate rises to 108 C. Thisstep requires about 0.5 hour. As the distillate-is removed, anequivalent quantity of dry butanol is continuously added to the reactionflask. After cooling, the butanol is removed by vacuum distillation andthe resin is recovered as a heavy viscous liquid.

EXAMPLEII' Example I is repeated except that the quantity ofN,N,N-tricyclohexylmelamine charged to the reaction is reduced to 19parts (0.05 mol). Similiarly, the quantity of n-butanol charged to thereaction is reduced to 220 parts (3.0 mol). The resin isobtained as athickviscous liquid.

EXAMPLE III Reactants consisting of 60 parts (1 mol) of urea, 19 parts(0.05 mol) of N,N,N"-tricyclohexylmelamine, 19 parts (0.18 mol) ofmelamine, 290 parts (3.58 mols) of formalin (37% formaldehyde), 300parts (4.05 mol) of butanol, and 4 parts of a 5% aqueous NaOH solutionare charged to the reaction vessel described in Example I. The alkalinesolution (pH=10.5) is refluxed for. 1.0 hour with all of the condensatebeing returned to the reaction flask.

After adjusting the pH of the system to 6.0 with oxalic acid, thereaction mixture is again heated to reflux. During this phase of thereaction, the decanting head is set to continuously remove the waterphase which separates in the distillation head and to returnthebuta'n'ol' phase to the reaction flask. A total of parts of waterphase is removed over a 5-hour period. The balance of the waterremaining in the reaction mixture is removed by refluxing the reactionmixture with the esterification head being set for total takeoff. Thedistillation is continued Ih ...s.tet requires. abQut....0.-. 5..lr 1911"As. thedistillatei asse ses removed, an equivalent quantity of drybutanol is continuously added to the reaction flask. After cooling, thebutanol is removed by vacuum distillation and the resin is recovered asa viscous liquid.

EXAMPLE 1v Example I is repeated except that theN,Nf,N"-t'ricyclohcxylmelamine is replaced with a stoichiornetricallyequivalent quantity of N,N'-dicyclohexylmelamine.

EXAMPLE v Reactants consisting of 370 parts (1.0 mol) of N,N',N"-tricyclohexylmelamine, 325 parts (4 mols) of formalin (37%formaldehyde), "600 parts (8 mols) of n-butanol and 4 parts of a 5%aqueous NaOH solution 'are charged to a reaction vessel equipped with astirrer and a condenser that is fitted with a "decantinge's't'erification head. The alkaline solution (pH- 105) is refluxed for1.0 hour with all of the condensate being returned to the reactionflask.

-Ait6r adjusting the PH bf the system to 6:4 with oxalic'aoidfithe'reactibn rnix'ture is again heatedto reflux. During thisphase or the reaction, the decanting head is set to continuously removethe water phase which separates in the distillation head and to returnthe butanol phase to the reaction "flask. -A total of 200 parts of waterphase is removed over a 1-hour period. The balance of the waterremaining in the reaction mixture is removed by refluxing the reactionmixture with the esterification head being set for total takeoff. Thedistillation is continued until the boiling point of the distillaterises to 108 CI This -step "requires about 0.5 hour. As thedistillate'is removed, an equivalent quantity of dry butanol is'conti'nu'ous'ly added to the reaction flask. After cooling, the resin"solution is concentrated t solids by removing additional butanolbyvacuum distillation.

EXAMPLE VI The following protective coating compositions are prepared'in which the figures listed are parts by weight:

Costing Composltirn's Component 1 a i n B 0 Control Resin 0! Example Il0. Resin Of E ample Il' Resin 0f Example Tll 10 Prior rt Resin 1- j 10Alk'ygl Reslr1.-., 20. 20 20 20 Titanium Dioxide- 25 25 25 25Blltaiioi;-.:.'-;- 10 10 10 10 35 35 35 35 The alkyd resin included inthe above compositions consists of a blend of two parts of a Jglycerylphthalate resin modified with 35 weight percent of coconut oil fattvacids and one part of a glyceryl phthalate resin modified with 40'weight percent of "soybean oil fatty acids. Prior Art Resin 1 includedin the control composition is a cominercially available butyl ether of aurea-formaldehyde resin.

Ascrie's of steelpanls are spray-coated with the above coatingcompositions and the fi1l'I'l S"8I'6 Cl.l1'e d byheatin'g for,respectively, 60 minutes at 180 F, 30 minutes at 225 F. and 20 minutesat 300 F. The-cured films are 2 mils thick. The Sward hardness'of eachof the films is measured and reported in Table I.

The detergent resistance of each of the films is measured by ASTM MethodD 114-45 in which the panels are maintained in an 0.5% aqueous detergentsolution at F. At each curing condition, the films prepared from theexperimental compositions are more resistant than the film prepared fromthe control composition.

The films prepared from the experimental coating compositions do notcrack when the steel panels are bent through C. over a conical mandrelas prescribed by ASTM Method D 522-41.

The above data indicate that coating compositions containing the novelurea-formaldehyde resins of this invention, as compared with coatingcompositions containing prior art urea-formaldehyde coating resins, l)cure faster, (2) provide harder films of superior flexibility and (3)provide films having superior detergent resistance.

EXAMPLE VII EXAMPLE VIII The following protective coating composition isprepared:

Component: Parts Alkyd resin 15.0 Resin of Example -IV 15.0 Titaniumdioxide a 15.0 Lam'pblaok -n 0.2 Xylol 40.0 Butanol 15.0

The alkyd resin included in the above formulation is a glyceryl'phthalate resin modified with about 42 weight percent of dehydratedcastor oil fatty acids. The coating composition is sprayed onto a steelpanel and baked for -20 minutes at 300 F. The resulting film is veryhard and has high gloss, good flexibility and good detergent resistance.

EXAMPLE IX -Four unpi'gmented, clear baking varnishes are prepared byincluding each of the resins of Example l-IV in the followingformulation:

Component: Parts Alkydresin 27.00 Aminoplastresin 3.00 Hydrocarbonsolvent u...... s 50.00 But'anol 5.00 Cob'alt naphthenate 0.06

The alkyd resin included in the formulation is a glyceryl phthalateresin modified with about '62 weight percent of soybean oil fatty acids.The hydrocarbon solvent is a commercial-mixture of petroleum aliphatichydrocarbons. The varnishes are sprayed onto steel panels and baked for20 minutes at 300 F. to provide hard films having high :gloss, :goodflexibility and ,good detergent resistance.

EXAMPLE X Protective coating compositions of the following formulationshave excellent properties and are included within the scope of the..present invention. Thefigures listed are parts -lJ'Y'V/tiighl.

Coating Composition Component A B C D E F G H I J K L M Resin t ExampleI 4 2 Resin Of Example IT Resin 01 Example III Resin Of Example IV 2Resin 0f Example V 2 2 1 1 1 Isobutyl Ether of a Urea- FormaldehydeResin 8 -7 7 7 7 7 Butyl Ether of a Urea-Formaldehyde Resin 6 6 6 6 8 77 Alkyd Resin--- 20 20 20 20 20 20 20 20 20 20 10 20 Titanium Dioxide 2525 25 25 25 25 25 25 25 25 25 Butauol 5 5 5 5 5 5 5 5 5 5 5 5 Xylol 4040 40 40 40 40 40 40 40 40 40 40 The alkyd resin employed is describedin Example VI. Both the butyl ether of the urea-formaldehyde resin andthe isobutyl ether of the urea-formaldehyde resin are commerciallyavailable resins.

Discussion The urea-formaldehyde resins of this invention are theetherified reaction product of at least 2 mols of a monohydric alcoholcontaining 1-6 carbon atoms and a cocondensation product of 1 mol ofurea, 0-0.3 mol of melamine, 0.020.5 mol of an N-substituted melamine ofthe group consisting of N,N'-dicyclohexylmelamine,N,N',N"-tricyclohexylmelamine and mixtures thereof, and at least 2 molsof formaldehyde. In a preferred embodiment of the invention, theurea-formaldehyde resins are the etherified reaction product of abutanol and a cocondensation product of urea,N,N,N"-tricyclohexylmelamine and formaldehyde. The co-condensatesemployed in the invention are prepared by heating the urea, the melamine(if any), the N- substituted melamine and the formaldehyde underalkaline conditions, e.g., at a pH of 85-105, in a suitable solvent suchas water, a 1-6 carbon atom monohydric alcohol or a water-alcoholmixture. If melamine is included in the co-condensate, it is employed inthe amount of up to 0.3 mol and preferably 0.020.2O mol per mol of urea.The quantity of N-substituted melamine employed is 0.02-0.5 orpreferably 0.050.2 mol per mol of urea. The minimum quantity offormaldehyde employed is at least 2 mols per mol of urea, but preferablythe formaldehyde is employed in a quantity sufiicient to react with eachof the reactive hydrogen atoms contained in the urea, the melamine (ifany) and the N-substituted melamine. In calculating the quantity offormaldehyde to be employed, urea is considered as containing 2 reactivehydrogen atoms, melamine contains 6 reactive hydrogen atoms,N,N-dicyclohexylmelamine contains 4 reactive hydrogen atoms, andN,N,N"-tricyclohexylmelamine contains 3 reactive hydrogen atoms. TheN,N-dicyclohexylmelamine employed in the invention may be obtained byreacting 2 mols of cyclohexylamine with 1 mol of 2,4-dichloro-6-amino-s-triazine and the N,N',N"-tricyclohexylmelamine may be obtainedby reacting 3 mols of cyclohexylamine with 1 mol of cyanuric chloride.Alternatively, both of these compounds may be prepared by the methoddisclosed in US. Patent 2,361,823.

The etherified resins are prepared by heating the cocondensate of urea,melamine (if any), the N-substituted melamine and formaldehyde with atleast 2 mols of a monohydric alcohol containing 1-6 or preferably 3-6carbon atoms under acid condition-s, e.g., at a pH of about 4.06.5.During this reaction, the co-condensation prodnot is both etherified andpolymerized. Thus, the alcohol functions as both a reactant and as asolvent for the reaction. Preferably, the reaction is carried out underreflux conditions (at either atmospheric or reduced pressure) so thatwater may be removed from the reaction system by azeotropicdistillation. To maintain the minimum quantity of alcoholrequired in thereaction system when operating under reflux conditions, it is necessary(1) to return the distilled alcohol to the reaction system, or (2) addalcohol to the reaction system as makeup, or (3) initially charge alarge excess of alcohol to the reaction. Essentially any l-6 carbon atommonohydric alcohol such as methanol, ethanol, propanol or hexanol may beemployed in the etherification reaction. The alcohol employed will to alarge degree be influenced by the use that is to be made of the resin.Where the resin is to be employed in protective coating compositions, weprefer to use n-butanol or especially isobutanol for this purpose. Afterthe etherification reaction is complete, the resin solutions may beconcentrated to the desired solids level or recovered in solvent-freeform by removing the solvent alcohol by vacuum distillation.

The resins of the invention may be used in the manufacture of textileprinting pastes, as an ingredient in adhesive formulations, in the resinfinishing of textiles (especially cottons), etc. The resins also may beused per se or in conjunction with other film-forming resins in thepreparation of protective coating compositions.

The present invention is also concerned with protective coatingcompositions which contain as the film-forming polymers a binary mixtureof a urea-formaldehyde resin of the type herein described and anoil-modified alkyd resin. The novel urea-formaldehyde resins arecompatible with alkyd resins of all oil lengths in virtually allproportions. Preferably, however, the resinous components of the coatingcompositions of primary concern consist of l050 weight percent of theurea-formaldehyde resin and, correspondingly, -50 weight percent of theoil-modified alkyd resin.

The invention further relates to protective coating compositions whichcontain as the film-forming polymers a ternary mixture of (1) a novelurea-formaldehyde resin of the type described above, 2) an etherifiedurea-formaldehyde resin and (3) an oil-modified alkyd resin. The

oil-modified alkyd resin ordinarily will constitute 50-90 weight percentof the total of the above 3 film-forming polymers. The novelurea-formaldehyde resin in turn ordinarily will constitute at least 20weight percent and preferably 2075 weight percent of the binary mixtureof the novel urea-formaldehyde resin and the etherified ureaformaldehyderesin. 7

" The etherified urea-formaldehyde resins included in the protectivecoating compositions described in the paragraph above are known in theart. Chemically, these resins are the etherified reaction product of atleast 2 mols of a monohydric alcohol containing 1-6 and preferably 3-6carbon atoms and a condensation product of 1 mol of urea and at leastabout 2 mols of formaldehyde. Preferably, the monohydric alcoholemployed to etherify the urea-formaldehyde condensate is a butanol suchas nbutanol or isobutanol.

In still another embodiment of the invention there are providedprotective coating compositions in which the film-forming polymersconsist of a ternary mixture of 1) an oil-modified alkyd resin, 2) anetherified urea-formaldehyde resin of the type described in theparagraph immediately above and (3) an etherified N-substitutedmelarnine-formaldehyde resin in which the N-substituted 7 melamine isselected from the group consisting of N,N- dicyclohexylmelamine,N,N,N"-tricyclohexylmelamine and mixtures thereof. The oil-modifiedalkyd resin ordinarily will constitute 50-90 weight percent of the totalof the above 3 film-forming polymers.

The etherified N-substituted melamine-formaldehyde resin in turn willconstitute 5-80 weight percent and preferably 5-30 weight percent of thebinary mixture of said etherified N-substituted melamine-formaldehyderesin and the etherified urea-formaldehyde resin.

The etherified N-substituted melamine-formaldehyde resins included inthe protective coating compositions described in the paragraphimmediately above are the etherified reaction product of at least 3 molsof a monohydric alcohol containing 1-6 and preferably 3-6 carbon atomsand a condensation product of 1 mol of an N- substituted melamine of the"group consisting of N,N'- dicyclohexylmelamine, N,N','N"tricyclohexylmelamine and mixtures thereof, and at least 1 mol offormaldehyde. In a preferred embodiment of the invention, these resinsare an etherified reaction product of nbutano-l or isobutanol and acondensation product of N,N,N"-tricyclohexylmelamine and formaldehyde. Adetailed description of such resin is contained in the co-pendingapplication of Harry M. Culbertson and Byron L. Williams, In, S.N.700,534 filed of even date herewith and that description is incorporatedherein by reference. The reference application and the presentapplication are owned by a common assignee.

In yet another embodiment of the invention there are provided protectivecoating compositions in which the film-forming polymers consist of 50-90weight percent of an oil-modified alkyd resin and, correspondingly, S-10 weight percent of a ternary mixture of aminoplast resins consistingof (a) a novel urea-formaldehyde resin of the type herein described, (b)an etherified ureaformaldehyde resin of the type described in the thirdparagraph above, and (c) an etherified N-substitutedmelamine-formaldehyde resin of the type described in the first paragraphabove. .In these compositions the component (0) constitutes about -80weight percent of the total of (a), (b) and (c). The remainingcomponents (a) and (b) may be included in virtually any desiredproportions but usually will be employed in a weight ratio of from 1:2to 2:1. Coating compositions (G), (H), (I) and (I) of Example Xillustrate this type of coating composition.

The alkyd resins employed in the protective coating compositions abovedescribed are the condensates of polyhydric alcohols such as glycols,glycerol, sorbitol, pentaerythritol, etc. with polybasic acids oranhydrides thereof, e.g., phthalic acid, phthalic anhydride, isophthalicacid, maleic acid, maleic anhydride, fumaric acid, adipic acid, azelaicacid, etc. These alkyd resins are modified with drying, semi-drying andnon-drying oils such as coconut oil, castor -'oil, dehydrated castoroil, soybean oil, linseed oil, tung oil, or the alcohols, acids andgycerides derived therefrom. The oil-modified alkyd resins having thebest balance of properties for inclusion in the protective coatingcompositions of the invention contan 30-70% and preferably 30-40% byweight of combined oil acids. As is known, such acids contain about12-20 carbon atoms.

The protective coating compositions of interest will comprise 20-70% ofthe mixture of the aminoplast resin (or resins) and the oil-modifiedalkyd resin dissolved in a suitable organic solvent such ashydrocarbons, alcohols, ethers, ketones, esters, and mixtures thereof,e.g., xylol-butanol and aliphatic hydrocarbon-butanol mixtures.Pigments, driers and other conventional ingredients may be included inthe coating compositions. Such compositions usually willbe formulated tohave a total solids content of about 40-60%.

The coating compositions of the invention may be advantageously employedto protect wooden, paper and 8 metal surfaces. The coating compositionsmay be ap: plied to the surfaces to be protected by conventional methodsof application such as ibrushing, spraying, roll coating, dipping, etc.The films may be cured by heating for short periods of time at -400 F".

The above descriptions and particularly the examples are set forth byway of illustration only. Many other variations and modifications of theinvention will be apparent to those skilled in the art and may beemployed without departing from the spirit and scope of the inventionherein described.

What is claimed is:

l. A resin comprising an etherified reaction product of at least 2 molsof a monohydric acyclic alcohol containing l-6 carbon atoms and aco-condensation product of 1 mol of urea, 0-03 mol of melamine, 0.02-0.5mol of an N-substi-tuted melamine of the group consisting ofN,N'-dicyclohexylmelamine, N,N, -tricyclohexylmelamine and mixturesthereof, and at least 2 mols of formaldehyde.

2. A resin comprising an etherified reaction product of at least 2 molsof n-butanol and a co-condensation product of 1 mol of urea, 0-0.3 molof melamine, 0.02- 0.5 mol of an N-substituted melamine of the groupconsisting of N,N-dicyclohexylmelamine, N,N',N"-tricyclohexylmelamineand mixtures thereof, and at least '2 mols of formaldehyde.

3. A resin comprising an etherified reaction product of at least 2 molsof n-butanol and a co-condensation product of 1 mol of urea, 0-0.3 molof melamine, 0.05- 0.2 .mol of N,NN"-tricyclohexylmelamine and at least2 mols of formaldehyde.

4. A resin comprising an etherified reaction product of at least 2 molsof .isobutanol and a co-condensation product of 1 mol of urea, 0-0.3 molof melamine, 0.05- 0.2 mol of N,N',N"-tricyclohexylmelamine and at least2 mols of formaldehyde.

5. A process for preparing a resin which comprises heating :1 .mol ofurea, 0-0.3 mol of melamine, 0.02-0.5 mol of an N-substituted melamineof the group consisting of N,N-dicyclohexylmelamine,N,N,N-tricyclohexylmelamine and mixtures thereof and at least 2 mols offormaldehyde in an aqueous medium under alkaline conditions toco-condense said reactants and then ether ifying said co-condensationproduct by heating said cocondensation product and at least 2 mols of amonohydric acyclic alcohol containing l-6 carbon atoms to substantiallyatmospheric reflux temperature under acidic conditions.

6. A protective coating composition comprising an organic solventsolution of a mixture of an oil-modified alkyd resin and an etherifiedreaction product of at least 2 mols of a monohydric acyclic alcoholcontaining 1-6 carbon atoms and a co'condensation product of l mol-ofurea, 0-0.3 mol of melamine, 0.02-0.5 mol of an N-substituted melamineof the group consisting of N,N'-dicyclohexylmelamine,N,N',N"-tricyclohexylmelamine and mixtures thereof and at least .2 molsof formaldehyde.

7. A protective coating composition as .in claim 6 wherein theoil-modified alkyd resin contains 30-70 weight percent of combined fattyacid moiety.

8. A protective coating composition comprising an organic solventsolution of a ternary mixture of (1) an oil-modified alkyd resin, (2) anetherified reaction prodnot of at least 2 mols of a .monohydric acyclicalcohol containing l-6 carbon atoms and a co-condensation product of 1mol of urea, 0-0.3 mol of melamine, 0.02-05 mol of an .N-substitutedmelamine of the group consisting of N,N -dicyclohexylmelamine,N,N,N-tricyclohexylmelamine and mixtures thereof and at least 2 mols offormaldehyde and (3) an etherified reaction product of at least 2 molsof a monohydric acyclic alcohol containing 1-6carbon atoms and acondensation product'of 1 mol of urea and at least .2 mols offormaldehyde; said 9 oil-modified alkyd resin constituting 5 -90 weightpercent of the total of (1), (2) and (3); said component (2)constituting at least 20 weight percent of the total of (2) and (3).

9. A protective coating composition as in claim 8 wherein theoil-modified alkyd resin contains 30-70 weight percent of combined fattyacid moiety.

10. A protective coating composition comprising an organic solventsolution of a ternary mixture of (1) an oil-modified alkyd resin, (2) anetherified reaction product of at least 2 mols of a monohydric acyclicalcohol containing l-6 carbon atoms and a condensation product of 1 molof urea and at least about 2 mols of formaldehyde and (3) an etherifiedreaction product of at least 3 mols of a monohydric acyclic alcoholcontaining 1-6 carbon atoms and a condensation product of 1 mol of anN-substituted melamine of the group consisting ofN,N'-dicyclohexylmelamine, N,N',N"-tricyclohexylmelamine and mixturesthereof and at least 1 mol of formaldehyde; said alkyd resinconstituting 50-90 weight percent of the total of 1), (2) and (3); saidcomponent (3) constituting -8-0 weight percent of the total of (2) and(3).

11. A protective coating composition as in claim 10 wherein theoil-modified alkyd resin contains 30-70 weight percent of combined fattyacid moiety.

12. A protective coating composition comprising an organic solventsolution of 50-90 weight percent of an oil-modified alkyd resin and,correspondingly, 50-10 weight percent of a ternary mixture of (a) anetherified reaction product of at least 2 mols of a monohydric acyclicalcohol containing 1-6 carbon atoms and a cocondensation product of 1mol of urea, 0-0.3 mol of melamine, 0.02-0.5 mol of an N-substitutedmelamine of the group consisting of N,N-dicyclohexylmelamine,N,N,N"-tricyclohexyrnelamine and mixtures thereof and at least 2 mols offormaldehyde, (b) an etherified reaction product of at least 2 mols of amonohydric acyclic alcohol containing 1-6 carbon atoms and acondensation product of 1 mol of urea and at least about 2 mols offormaldehyde and (c) an etherified reaction product of at least 3 molsof a monohydric acyclic alcohol containing 1-6 carbon atoms and acondensation product of 1 mol of an N-substituted melamine of the groupconsisting of N,N- dicyclohexylmelamine, N,N',N"-tricyclohexylmelamineand mixtures thereof and at least 1 mol of formaldehyde, said component(c) constituting 5-80 weight percent of the total of (a), (b) and (c).

13. A protective coating composition comprising an organic solventsolution of a mixture of an oil-modified alkyd resin and an aminoplastresin of the group consisting of (a) an etherified reaction product ofat least 2 mols of a monohydric acyclic alcohol containing 1-6 carbonatoms and a co-condensation product of 1 mol of urea, 0-0.3 mol ofmelamine, 0.02-0.5 mol of an N-substituted melamine and at least 2 molsof formaldehyde; (b) a binary mixture of (1) an etherified reactionproduct of at least 2 mols of a monohydric acyclic alcohol containing1-6 carbon atoms and a co-condensation product of 1 mol of urea, 0-0.3mol of melamine, 0.02-0.5 mol of an N-substituted melamine and at least2 mols of formaldehyde and (2) an etherified reaction product of atleast 2 mols of a monohydric acyclic alcohol containing 1-6 carbon atomsand a condensation product of 1 mol of urea and at least 2 mols offormaldehyde, said component (1) constituting at least 20 weight percentof the total of (1) and (2); (c) a binary mixture of (3) an etherifiedreaction product of at least 2 mols of a monohydric acyclic alcoholcontaining 1-6 carbon atoms and a condensation product of 1 mol of ureaand at least about 2 mols of formaldehyde and (4) an etherified reactionproduct of at least 3 mols of a monohydric acyclic alcohol containing1-6 carbon atoms and a condensation product of 1 mol of an N-substitutedmelamine and at least 1 mol of formaldehyde, said component (4)constituting 5-80 Weight percent of the total of (3) and (4); and (d) aternary mixture (5) of an etherified reaction product of at least 2 molsof a monohydric acyclic alcohol containing 1-6 carbon atoms and aco-condensatron product of 1 mol of urea, 0.03 mol of melamine, 0.02-0.5mol of an N-substituted melamine and at least 2 mols of formaldehyde,(6) an etherified reaction product of at least 2 mols of a monohydricacyclic alcohol containing 1-6 carbon atoms and a condensation productof 1 mol of urea and at least 2 mols of formaldehyde, (7) an etherifiedreaction product of at least 3 mols of a monohydric acyclic alcoholcontaining 1-6 carbon atoms and a condensation product of 1 mol of an N-substituted melamine and at least 1 mol of formaldehyde, said component(7) constituting 5-80 weight percent of the total of (5), (6) and (7);the N-substituted melamine included in aminoplast resins (a), (1), (4),(5) and (7 being selected from the group consisting of N,N-dicyclohexylmelamine, N,N',N"-tricyclohexylmelamine and mixturesthereof.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Hodgins et al.: Melamine-Formaldehyde Film FormingCompositions, pages 769-779, 1nd. & Eng. Chem, Vol. 33, No. 6 (June1941).

UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No2,959,558 November 8, 1960 Harry Mo Culbertson et al0 It is herebycertified that error appears in the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Columns 5 and 6, in the Table, under column "K" thereof, the thirdfigure therein, for "10" read 20 column 10, line 25, for "0003" readO-O.3

Signed and sealed this 2nd day of May 1961,

(SEAL) Attest:

ERNEST W. SWIDER DAVID L, LADD Attesting Officer Commissioner of Patents

1. A RESIN COMPRISING AN ETHERIFIED REACTION PRODUCT OF AT LEAST 2 MOLSOF A MONOHYDRIC ACYCLIC ALCOHOL CONTAINING 1-6 CARBON ATOMS AND ACO-CONDENSATION PRODUCT OF 1 MOL OF UREA, 0-0.3 MOL OF MELAMINE,0.02-0.5 MOL OF AN N-SUBSTITUTED MELAMINE OF THE GROUP CONSISTING OFN,N''-DICYCLOHEXYLMELAMINE, N,N'',N"-TRICYCLOHEXYLMELAMINE AND MIXTURESTHEREOF, AND AT LEAST 2 MOLS OF FORMALDEHYDE.